As mobile computing and communication devices become more prevalent, the need for additional services and functionality increases as well. For example, mobile communication devices such as cell phones were originally intended simply to allow a mobile user to communicate telephonically from remote locations without the need to locate a landline such as a pay phone. As cellular technology and devices increased in prevalence, users began to demand and receive additional services unique to the mobile environment. For example, many cellular communication devices are now used in a highly mobile environment where real-time location-based services are needed. Indeed, many vehicles now come equipped with cellular wireless telematics units, and the need for navigation assistance, weather data, traffic reports, and other location-based information has increased accordingly.
The provision of location-based information and services entails overcoming a number of challenges, but the first step in providing such services is the accurate identification of a mobile node's location.
Location detection and identification implementations are generally either control-plane applications or user-plane applications. Control plane applications use the network signaling capabilities, e.g., IS-41 signaling networks, as a means to detect the location of the mobile node. The “E911” service is an example of a well-known control plane application. Control plane location detections are typically network initiated.
In contrast, user plane implementations use the IP network and protocols rather than the signaling network for location data requests and transmission. Although all user plane implementations are IP-based, there are different possible user plane implementations with this group. For example, user plane implementations can operate according to either a “Trusted” or “Non-Trusted” model. The trusted model assumes that the location client/application are trusted, and thus no authentication of the client is required. In this model, there are no network initiated location requests. In contrast, the non-trusted model requires that the location requesting entity to be authenticated, thus allowing for both network initialed and mobile initiated location requests.
Both control and user plane implementations use a Base Station Almanac (BSA) lookup to provide an initial location determination. However, user plane implementations employ the system ID (SID, used to determine a home network from a roaming network), network ID (NID), BASEID and PN-OFFSET as keys for the BSA lookup operation. In contrast, the control plane implementations use the Switch number as a key for the BSA lookup operation. The BASE ID can be a Base Station ID, e.g., a unique number within a cellular system that identifies each cell site. The PN-OFFSET can be a unique number identifying a sector within a base station that operates according to a CDMA-based access technology standard.
Although there are also proprietary solutions that do not completely fit the above categorizations, such solutions often have features similar to one or more of the foregoing categories. Thus, available location detection implementation currently include control-plane, trusted user plane, non-trusted user plane, and proprietary solutions. In view of this wide variety of location detection implementations, the likelihood of a user device needing to operate within more than one implementation is substantial. For example, location detection while roaming is an issue in such a heterogeneous implementation. No inter-working solution exists, and as a result, current roaming solutions simply assume, often incorrectly, that the visited and home networks offer similar location detection solutions.